Rubber crosslinking accelerator, sidewall rubber composition, sidewall rubber material and preparation method and application thereof

Abstract

The invention provides a rubber crosslinking accelerator, a sidewall rubber composition, a sidewall rubber material and a preparation method and application thereof. The rubber crosslinking accelerator comprises octachlorocyclopentadiene, triethanolamine and lead oxide, and the mass ratio of the octachlorocyclopentadiene to the triethanolamine to the lead oxide is (1.0-3.0): (0.5-1.5): (1.0-3.0). In the rubber cross-linking accelerator provided by the invention, octachlorocyclopentadiene can be used as a cross-linking agent of diene rubber, lead oxide is used as a chlorine acceptor, triethanolamine is used as a chlorine active agent, and the octachlorocyclopentadiene, lead oxide and triethanolamine have a synergistic effect under a specific ratio, so that part of traditional vulcanizing agents and accelerators can be replaced; a carbon-carbon single bond is generated in the crosslinking process of a rubber matrix, the bond energy of the carbon-carbon single bond is remarkably higher than that of a sulfur-containing bond, and the chemical stability of the carbon-carbon single bond is higher, so that the vulcanized rubber with the carbon-carbon single bond has remarkable advantages in high temperature resistance and acid and alkali corrosion resistance.

Description

Technical Field

[0001] This application relates to the field of tire rubber compound production, and more specifically, to a rubber crosslinking accelerator, a sidewall rubber composition, a sidewall compound, and its preparation method and application. Background Technology

[0002] Railcars are the primary transportation tools for railway equipment maintenance, infrastructure construction, and other construction departments. These vehicles require tires with sufficiently high load-bearing capacity. Due to the heavy load and high speed of the vehicles, the tires generate significant heat. Furthermore, the relatively enclosed space of the railcar makes heat dissipation difficult, resulting in extremely high localized temperatures that severely impact tire lifespan. Therefore, railcars impose more stringent requirements on the high-temperature aging resistance of all rubber components in the tires. Simultaneously, during use, tires inevitably come into contact with acids, alkalis, and corrosive chemicals. Acids can disrupt the atomic arrangement of C and H atoms in rubber molecules, accelerating tire aging, while alkalis also readily accelerate rubber aging, leading to a reduction in tire lifespan.

[0003] The tire sidewall, located on the outer surface of the tire, undergoes frequent radial and flexural deformation during operation. Furthermore, it is in direct contact with the air at sustained high temperatures. At high temperatures, gases such as oxygen in the air accelerate the reaction with rubber hydrocarbons, thus speeding up the aging process of the tire sidewall. Especially for railcar tires, which operate in a relatively enclosed environment where heat cannot dissipate quickly, the ambient temperature is much higher than that of conventional tires, thus requiring even higher high-temperature resistance from the tire sidewall. Due to the extremely high loads and harsh operating environments of railcars, including exposure to acids and alkalis during operation, the tire sidewall also requires extremely high resistance to acid and alkali corrosion. The high-temperature and corrosion resistance of the tire sidewall directly affects the tire's flexural properties, and consequently, its service life.

[0004] Existing technologies for improving the heat and oxygen aging resistance of vulcanizates include increasing the content of antioxidants in the system and using peroxide vulcanization systems. However, various antioxidants have a certain optimal dosage range in vulcanizates. When the antioxidant content exceeds a certain range, it can cause blooming of the antioxidants and a deterioration in the aging resistance of the vulcanizate. Using peroxide vulcanization systems can cause problems with co-vulcanization between rubber components, leading to premature tire damage. Therefore, current methods for improving the high-temperature resistance of tires are still insufficient, and there are no patent reports on high-temperature resistant and acid and alkali corrosion resistant sidewall rubber compositions developed for rail vehicle tire sidewalls.

[0005] In view of the above, this application is hereby submitted. Summary of the Invention

[0006] The main objective of this application is to provide a rubber crosslinking accelerator, a sidewall rubber composition, a sidewall compound, and its preparation method and application, in order to solve the problem that the sidewall rubber of tires has poor heat and oxygen aging resistance and acid and alkali corrosion aging resistance in the prior art, which leads to accelerated tire aging and reduced service life.

[0007] To achieve the above objectives, according to one aspect of this application, a rubber crosslinking accelerator is provided, comprising octachlorocyclopentadiene, triethanolamine, and lead oxide, wherein the mass ratio of the three is (1.0–3.0):(0.5–1.5):(1.0–3.0).

[0008] According to a second aspect of this application, a sidewall rubber composition is also provided, comprising, by weight parts: 100 parts of a base rubber, 2.5 to 7.5 parts of the rubber crosslinking accelerator provided in the first aspect, 0.1 to 0.8 parts of the accelerator, and 0.2 to 1.0 parts of the vulcanizing agent.

[0009] Furthermore, in the sidewall rubber composition, based on 100 parts by weight of the base rubber, the amount of octachlorocyclopentadiene is 1.0 to 3.0 parts by weight, the amount of triethanolamine is 0.5 to 1.5 parts by weight, and the amount of lead oxide is 1.0 to 30 parts by weight.

[0010] Furthermore, the base rubber includes natural rubber, butadiene rubber, and styrene-butadiene rubber. Based on 100 parts by weight of the base rubber, the amount of natural rubber is 40.0 to 50.0 parts by weight, the amount of butadiene rubber is 40.0 to 55.0 parts by weight, and the amount of styrene-butadiene rubber is 5.0 to 20.0 parts by weight.

[0011] Furthermore, the accelerator is accelerator NS.

[0012] Furthermore, the vulcanizing agent is sulfur.

[0013] Furthermore, the rubber composition also includes at least one of fillers and additives.

[0014] Furthermore, in the rubber composition, the amount of filler is 40.0 to 55.0% by mass, based on 100 parts by mass of the base rubber.

[0015] Furthermore, in the rubber composition, based on 100 parts by weight of the base rubber, the additives include 2.8 to 7.5 parts by weight of an antioxidant, 3.5 to 9.0 parts by weight of an activator, and 0.1 to 0.3 parts by weight of an anti-scorching agent.

[0016] Furthermore, the filler is carbon black, including at least one of carbon black N330, carbon black N347, carbon black N375, carbon black N326, and carbon black N351.

[0017] Furthermore, antioxidants include at least one of wax-based antioxidants, quinoline-based antioxidants, and p-phenylenediamine-based antioxidants.

[0018] Furthermore, based on 100 parts by weight of the base rubber, the rubber composition includes 0.8-2.0 parts by weight of wax antioxidant, 1.0-2.5 parts by weight of quinoline antioxidant, and 1.0-3.0 parts by weight of p-phenylenediamine antioxidant.

[0019] Furthermore, wax-based antioxidants include at least one of the protective waxes WAX111 and HG72.

[0020] Furthermore, quinoline antioxidants include antioxidant RD.

[0021] Furthermore, p-phenylenediamine antioxidants include antioxidant 4020.

[0022] Furthermore, the scorching inhibitor is CTP.

[0023] Furthermore, the surfactants include zinc oxide and stearic acid.

[0024] Furthermore, the rubber composition comprises 2.5 to 6.0 parts by weight of zinc oxide and 1.0 to 3.0 parts by weight of stearic acid per 100 parts by weight of the base rubber.

[0025] According to a third aspect of this application, a sidewall compound is also provided, the raw material of which is the rubber composition provided in the second aspect above.

[0026] According to a fourth aspect of this application, a method for preparing a sidewall compound is also provided, comprising the following steps: mixing and vulcanizing a base rubber, filler, rubber crosslinking accelerator, vulcanizing agent and accelerator to obtain a sidewall compound.

[0027] According to the fifth aspect of this application, the application of the rubber crosslinking accelerator provided in the first aspect, the sidewall rubber composition provided in the second aspect, or the sidewall compound provided in the third aspect in a tire is also provided.

[0028] Applying the technical solution of this application, the rubber crosslinking accelerator provided includes octachlorocyclopentadiene, triethanolamine, and lead oxide. Octachlorocyclopentadiene can act as a crosslinking agent for diene rubbers, lead oxide acts as a chlorine acceptor, and triethanolamine acts as a chlorine activator. These three components work synergistically in a specific ratio, capable of replacing some traditional vulcanizing agents and accelerators. Unlike traditional sulfur and sulfenamide accelerator systems, the rubber crosslinking accelerator provided in this application generates carbon-carbon single bonds during the crosslinking process of the rubber matrix, rather than sulfur-containing bonds (such as monosulfide, disulfide, or polysulfide bonds) in traditional systems. The bond energy of carbon-carbon single bonds is significantly higher than that of sulfur-containing bonds, resulting in stronger chemical stability. Therefore, vulcanized rubber with carbon-carbon single bonds has significant advantages in high-temperature resistance and acid and alkali corrosion resistance. In contrast, traditional sulfur-containing bonds are easily broken under high-temperature or acid / alkali environments, leading to a decline in the performance of the vulcanized rubber. Based on this characteristic, the rubber crosslinking accelerator provided in this application can significantly improve the high temperature resistance and acid and alkali corrosion resistance of vulcanizates, thereby improving the anti-aging properties and service life of vulcanizates, and is suitable for the field of rubber products with high durability requirements. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0030] As described in the background section of this application, the rubber used in the sidewalls of current engineering tires has poor resistance to heat and oxygen aging, as well as acid and alkali corrosion aging, leading to accelerated aging and reduced service life. To address this problem, this application provides a rubber crosslinking accelerator, a sidewall rubber composition, a sidewall compound, its preparation method, and its application.

[0031] In a first typical embodiment of this application, a rubber crosslinking accelerator is provided, which includes octachlorocyclopentadiene, triethanolamine and lead oxide, and the mass ratio of octachlorocyclopentadiene, triethanolamine and lead oxide is (1.0~3.0):(0.5~1.5):(1.0~3.0).

[0032] The rubber crosslinking accelerator provided in this application includes octachlorocyclopentadiene, triethanolamine, and lead oxide. Octachlorocyclopentadiene can act as a crosslinking agent for diene rubbers, lead oxide acts as a chlorine acceptor, and triethanolamine acts as a chlorine activator. These three components work synergistically in a specific ratio, capable of replacing some traditional vulcanizing agents and accelerators. Unlike traditional sulfur and sulfenamide accelerator systems, the rubber crosslinking accelerator provided in this application generates carbon-carbon single bonds during the crosslinking process of the rubber matrix, rather than sulfur-containing bonds (such as monosulfide, disulfide, or polysulfide bonds) in traditional systems. The bond energy of carbon-carbon single bonds is significantly higher than that of sulfur-containing bonds, resulting in stronger chemical stability. Therefore, vulcanized rubber with carbon-carbon single bonds exhibits significant advantages in high-temperature resistance and acid / alkali corrosion resistance. In contrast, traditional sulfur-containing bonds are prone to breakage under high-temperature or acid / alkali environments, leading to a decline in the performance of the vulcanized rubber. Based on this characteristic, the rubber crosslinking accelerator provided in this application can significantly improve the high temperature resistance and acid and alkali corrosion resistance of vulcanizates, thereby improving the anti-aging properties and service life of vulcanizates, and is suitable for the field of rubber products with high durability requirements.

[0033] The reaction mechanism of rubber crosslinking accelerator inducing rubber crosslinking is as follows: 2R-H + 2R'-Cl + PbO -> R-R + R'-R' + PbCl2 + H2O. Here, R and R' represent residues formed by the loss of H in diene rubber molecules, RH represents diene rubber molecules that have not lost H, and R'-Cl represents diene rubber molecules formed by Cl replacing H.

[0034] Typically, but not limitingly, the mass ratios of octachlorocyclopentadiene, triethanolamine, and lead oxide in the rubber crosslinking accelerator provided in this application are, for example, 1:0.5:1.0, 1:0.5:3.0, 1:1.5:1.0, 1:1.5:3.0, 3.0:0.5:1.0, 3.0:0.5:3.0, 3.0:1.5:1.0, 3.0:1.5:3.0, or any range of two values.

[0035] In a second typical embodiment of this application, a sidewall rubber composition is provided, comprising, by weight parts: 100 parts of base rubber, 2.5 to 7.5 parts of the rubber crosslinking accelerator provided in the first typical embodiment, 0.1 to 0.8 parts of accelerator, and 0.2 to 1.0 parts of vulcanizing agent.

[0036] The sidewall rubber composition provided in this application significantly improves the high-temperature aging resistance and acid and alkali corrosion aging resistance of rubber by adding a rubber crosslinking accelerator including octachlorocyclopentadiene, triethanolamine, and lead oxide, thus extending the service life of the rubber. Compared with traditional sulfur and sulfenamide accelerator systems, the rubber crosslinking accelerator in this application generates carbon-carbon single bonds during the crosslinking process of the rubber matrix, rather than sulfur-containing bonds (such as monosulfide, disulfide, or polysulfide bonds) in traditional systems. Octachlorocyclopentadiene in the rubber crosslinking accelerator acts as a crosslinking agent for diene rubbers, lead oxide acts as a chlorine acceptor, and triethanolamine acts as a chlorine activator. Utilizing the synergistic effect of these three components, the matrix rubber is crosslinked through carbon-carbon single bonds, and this accelerator can replace some traditional vulcanizing agents and accelerators. The bond energy of carbon-carbon single bonds is significantly higher than that of sulfur-containing bonds, resulting in stronger chemical stability. Even under high temperature or chemically corrosive environments, carbon-carbon single bonds remain stable and are not easily broken, thus significantly improving the high-temperature aging resistance and acid and alkali corrosion aging resistance of the vulcanized rubber. This technological breakthrough enables rubber products to exhibit excellent performance under extreme conditions, and has broad application prospects.

[0037] Typical, but not limiting, the sidewall rubber composition provided in this application, based on 100 parts by weight of the base rubber, includes the following amounts: the amount of rubber crosslinking accelerator is 2.5 parts by weight, 3.5 parts by weight, 4.5 parts by weight, 5.5 parts by weight, 6.5 parts by weight, 7.5 parts by weight, or any combination of two values; the amount of accelerator is 0.1 parts by weight, 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 0.8 parts by weight, or any combination of two values; and the amount of vulcanizing agent is 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 0.8 parts by weight, 1.0 parts by weight, or any combination of two values.

[0038] Rubber crosslinking accelerator

[0039] To improve the high-temperature resistance and corrosion aging resistance of vulcanizates, a rubber crosslinking accelerator comprising octachlorocyclopentadiene, triethanolamine, and lead oxide is added to the rubber composition. Octachlorocyclopentadiene acts as a crosslinking agent for diene rubbers, lead oxide as a chlorine acceptor, and triethanolamine as a chlorine activator. Utilizing the synergistic effect of these three components, the matrix rubbers are crosslinked through carbon-carbon single bonds, and they can replace some traditional vulcanizing agents and accelerators. Carbon-carbon single bonds have high bond energy and stronger chemical stability. Even under high temperatures or chemically corrosive environments, carbon-carbon single bonds remain stable and are not easily broken, thus significantly improving the high-temperature resistance and acid / alkali corrosion aging resistance of the vulcanizate.

[0040] In the rubber composition provided in the application, based on 100 parts by weight of the base rubber, the amount of octachlorocyclopentadiene is 1.0 to 3.0 parts by weight, the amount of triethanolamine is 0.5 to 1.5 parts by weight, and the amount of lead oxide is 1.0 to 3.0 parts by weight. When the content of any one or more of lead oxide, triethanolamine, and octachlorocyclopentadiene is too low, it will result in a low crosslinking density, and the vulcanized rubber will have low tensile stress and hardness. When the content of any one or more of lead oxide, triethanolamine, and octachlorocyclopentadiene is too high, it will result in a high crosslinking density, and the vulcanized rubber will have high hardness and tensile stress, and poor flexural properties.

[0041] Typical, but not limiting, amounts of octachlorocyclopentadiene, based on 100 parts by weight of the base rubber, may be 1.0, 1.5, 2.0, 2.5, 3.0 parts by weight, or any range of two such values; amounts of triethanolamine, such as 0.5, 0.8, 1.0, 1.2, 1.5 parts by weight, or any range of two such values; and amounts of lead oxide, such as 1.0, 1.5, 2.0, 2.5, 3.0 parts by weight, or any range of two such values.

[0042]

Base Rubber

[0043] The base rubber is a commonly used rubber in this field, including but not limited to one or more of natural rubber, styrene-butadiene rubber (SBR), and butadiene rubber. Natural rubber has irreplaceable advantages in tire manufacturing; its high elasticity, tear resistance, abrasion resistance, and good grip make it an essential component of high-performance tires. When used in the sidewall compound, natural rubber provides good flexibility and fatigue resistance, increasing tire durability and impact resistance. SBR has excellent abrasion resistance, wet skid resistance, and aging resistance, effectively resisting ozone and ultraviolet radiation, improving tire durability, and has lower production costs, effectively improving economic efficiency. Butadiene rubber has excellent cold resistance and low heat generation, preventing hardening even in low-temperature environments and reducing heat generation during prolonged use.

[0044] To further improve the overall performance of the rubber compound, in some embodiments, the base rubber includes natural rubber, butadiene rubber, and styrene-butadiene rubber. Based on 100 parts by weight of the base rubber, the amount of natural rubber is 40.0 to 50.0 parts by weight, the amount of butadiene rubber is 40.0 to 55.0 parts by weight, and the amount of styrene-butadiene rubber is 5 to 20.0 parts by weight.

[0045] Typical, but not limiting, the amounts of natural rubber used, based on 100 parts by weight of the base rubber, are 40.0 parts by weight, 42.0 parts by weight, 44.0 parts by weight, 46.0 parts by weight, 48.0 parts by weight, 50.0 parts by weight, or any range of two such values; the amounts of butadiene rubber used are 40.0 parts by weight, 44.0 parts by weight, 48.0 parts by weight, 52.0 parts by weight, 55.0 parts by weight, or any range of two such values; and the amounts of styrene-butadiene rubber used are 5.0 parts by weight, 10.0 parts by weight, 15.0 parts by weight, 20.0 parts by weight, or any range of two such values.

[0046] In some specific embodiments, the natural rubber mentioned above is one or more of natural rubber SMR20, natural rubber STR20, and natural rubber TSR20.

[0047] In some specific embodiments, the above-mentioned styrene-butadiene rubber is solution-polymerized styrene-butadiene rubber (SSBR), specifically, styrene-butadiene rubber (SSBR) is SSBR-HPR850, etc.

[0048] In some specific embodiments, the aforementioned butadiene rubber is butadiene rubber BR9000, etc.

[0049] Given that engineering tires encounter complex and varied environments during use, and that different vehicle types have significantly different requirements for tires, the types and contents of natural rubber, butadiene rubber, and styrene-butadiene rubber in the formulation are adjusted according to the specific needs of the vehicle and environment in order to meet the requirements of engineering tires in various load environments.

[0050] Vulcanizing agent

[0051] To improve the co-vulcanization characteristics of tire interfaces, a vulcanizing agent is added to a high-temperature and corrosion-resistant rubber composition. The vulcanizing agent reacts with specific functional groups on the rubber molecular chain to form chemical cross-linking bonds, thereby cross-linking the linear rubber molecular chain into a three-dimensional network structure. Vulcanization further improves the mechanical properties of the rubber and its resistance to high temperature and chemical corrosion, and is conducive to improving the co-vulcanization characteristics of different tire interfaces, thus further improving the service life of the tire.

[0052] The specific type of vulcanizing agent used in this application is not limited; any commonly used vulcanizing agent in the field may be used. From the perspective of its broad applicability to rubber products, sulfur is preferred.

[0053] Accelerator

[0054] To improve the crosslinking efficiency between the vulcanizing agent and rubber molecules and achieve rapid and uniform vulcanization of rubber products, an accelerator is added to the high-temperature and corrosion-resistant rubber composition.

[0055] The specific type of accelerator is not limited in this application; any commonly used accelerator in the field is acceptable. From an environmental perspective, accelerator NS is preferred.

[0056]

filler

[0057] To further improve the overall performance of the rubber compound, such as mechanical strength, anti-aging properties, and processing performance, the preferred high-temperature and corrosion-resistant rubber composition also includes any one or more fillers and additives.

[0058] Fillers, by dispersing within the base rubber and interacting with it, further enhance the mechanical strength of the rubber compound, including tensile strength, tear strength, and abrasion resistance. Furthermore, fillers promote mixing uniformity, thereby further improving the processing properties of the rubber compound.

[0059] To further improve the mechanical properties of the rubber compound, the filler content is preferably 40.0 to 55.0 parts by weight per 100 parts by weight of the base rubber.

[0060] Typical, but not limiting, in the high-temperature and corrosion-resistant rubber composition provided in this application, the filler content is preferably 40.0 parts by weight, 45.0 parts by weight, 50.0 parts by weight, 55.0 parts by weight, or any range of two values, based on 100 parts by weight of the base rubber.

[0061] The specific type of filler used in this application is not limited, and any filler commonly used in the art is acceptable. In order to further improve the mechanical strength of the rubber compound, carbon black is preferred as the filler, and carbon black is further preferred to include any one or more of carbon black N330, carbon black N347, carbon black N375, carbon black N326, and carbon black N351.

[0062] [Additives]

[0063] To further improve the overall performance of the rubber compound, such as anti-aging properties, vulcanization effect and processing stability, the preferred additives include at least one of antioxidants, activators and anti-scorching agents. Based on 100 parts by weight of the base rubber, the preferred additives include 2.8 to 7.5 parts by weight of antioxidants, 3.5 to 9.0 parts by weight of activators and 0.1 to 0.3 parts by weight of anti-scorching agents.

[0064] Typical, but not limiting, the high-temperature and corrosion-resistant rubber composition provided in this application, based on 100 parts by weight of the base rubber, includes an antioxidant in an amount of 2.8 parts by weight, 3.5 parts by weight, 4.5 parts by weight, 5.5 parts by weight, 6.5 parts by weight, 7.5 parts by weight, or any range of two such values; an activator in an amount of 3.5 parts by weight, 4.0 parts by weight, 5.0 parts by weight, 6.0 parts by weight, 7.0 parts by weight, 8.0 parts by weight, 9.0 parts by weight, or any range of two such values; and an anti-scorching agent in an amount of 0.1 parts by weight, 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, or any range of two such values.

[0065] Anti-aging agents

[0066] The antioxidants mentioned above are commonly used in this field, including but not limited to any one or more of wax antioxidants, quinoline antioxidants, and p-phenylenediamine antioxidants.

[0067] During the use of rubber, wax-based antioxidants can migrate to the rubber surface and form a wax film. This film effectively isolates the rubber from the erosion of oxygen, ultraviolet rays, and chemicals, further improving the anti-aging properties of the rubber compound. Specifically, protective waxes are preferred, such as protective wax WAX111 and protective wax HG72.

[0068] Quinoline antioxidants can inhibit rubber aging at the molecular level, especially exhibiting excellent antioxidant and ozone aging resistance, thereby extending the service life of rubber compounds. Specifically, antioxidant RD (Chinese name: 2,2,4-trimethyl-1,2-dihydroquinoline polymer) is preferred among quinoline antioxidants.

[0069] p-Phenylenediamine antioxidants can capture or combine with free radicals generated during rubber oxidation to form stable compounds, thereby effectively inhibiting oxidation reactions and further improving the anti-aging properties of rubber compounds. Specifically, antioxidant 4020 (Chinese name: N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine) is preferred among p-phenylenediamine antioxidants.

[0070] In some embodiments, based on 100 parts by weight of the base rubber, the amount of wax-based antioxidant is 0.8-2.0 parts by weight; the amount of quinoline-based antioxidant is 1.0-2.5 parts by weight; and the amount of p-phenylenediamine-based antioxidant is 1.0-3.0 parts by weight, more preferably 1.0-2.5 parts by weight. By utilizing the synergistic effect between different antioxidants at specific dosages, the anti-aging properties of the rubber compound can be further improved, and its service life extended.

[0071] Typical, but not limiting, amounts of wax-based antioxidants, based on 100 parts by weight of the base rubber, may be 0.8 parts by weight, 1.2 parts by weight, 1.6 parts by weight, 2.0 parts by weight, or any range of two such values; amounts of quinoline-based antioxidants, such as 1.0 parts by weight, 1.5 parts by weight, 2.0 parts by weight, 2.5 parts by weight, or any range of two such values; and amounts of p-phenylenediamine-based antioxidants, such as 1.0 parts by weight, 1.5 parts by weight, 2.0 parts by weight, 2.5 parts by weight, 3.0 parts by weight, or any range of two such values.

[0072] Surfactants

[0073] In some embodiments, the activator includes zinc oxide and stearic acid. Zinc oxide and stearic acid react to form zinc stearate, which dissolves in the rubber and contacts the accelerator and vulcanizing agent more uniformly, further improving the vulcanization reaction efficiency. Preferably, the zinc oxide is indirect zinc oxide, utilizing zinc oxide with higher purity and dispersibility to further enhance vulcanization activity.

[0074] To further enhance the synergistic effect of zinc oxide and stearic acid during vulcanization, thereby improving the performance of the rubber compound, the preferred dosage of zinc oxide is 2.5–6.0 parts by weight and the dosage of stearic acid is 1.0–3.0 parts by weight, based on 100 parts by weight of the base rubber. In particular, when the dosage of zinc oxide is 2.5–5.0 parts by weight and the dosage of stearic acid is 1.5–3.0 parts by weight, it is more conducive to improving the performance of the rubber compound.

[0075] Typical, but not limiting, amounts of zinc oxide, such as 2.5 parts by weight, 3.0 parts by weight, 4.0 parts by weight, 5.0 parts by weight, 6.0 parts by weight, or any range of two such values, per 100 parts by weight of the base rubber; and amounts of stearic acid, such as 1.0 parts by weight, 1.5 parts by weight, 2.0 parts by weight, 2.5 parts by weight, 3.0 parts by weight, or any range of two such values.

[0076] Anti-scorching agent

[0077] Adding an anti-scorching agent to a high-temperature and corrosion-resistant rubber composition further prevents premature vulcanization of the rubber compound during processing, delays the vulcanization reaction, and prevents scorching.

[0078] The above-mentioned anti-scorching agents are commonly used in this field. Any commonly used anti-scorching agents in this field are acceptable. From the perspective of reducing costs, the preferred anti-scorching agent is CTP (N-cyclohexylthiophthalimide).

[0079] To further prevent scorching of the rubber compound, the preferred amount of anti-scorching agent is 0.1 to 0.25 parts by weight per 100 parts by weight of the base rubber.

[0080] In a third typical embodiment of this application, a sidewall compound is also provided, the raw material of which is the rubber composition provided in the second typical embodiment described above.

[0081] The sidewall rubber compound provided in this application incorporates a rubber crosslinking accelerator, comprising octachlorocyclopentadiene, triethanolamine, and lead oxide. Octachlorocyclopentadiene acts as a crosslinking agent for diene rubbers, lead oxide as a chlorine acceptor, and triethanolamine as a chlorine activator. These three components work synergistically in a specific ratio, capable of replacing some traditional vulcanizing agents and accelerators. Unlike traditional sulfur and sulfenamide accelerator systems, the rubber crosslinking accelerator provided in this application generates carbon-carbon single bonds during the rubber crosslinking process, rather than sulfur-containing bonds (such as monosulfide, disulfide, or polysulfide bonds) found in traditional systems. The bond energy of carbon-carbon single bonds is significantly higher than that of sulfur-containing bonds, resulting in stronger chemical stability. Therefore, vulcanized rubber containing carbon-carbon single bonds exhibits significant advantages in high-temperature resistance and acid / alkali corrosion resistance. In contrast, traditional sulfur-containing bonds are prone to breakage under high-temperature or acid / alkali environments, leading to a decline in the performance of the vulcanized rubber. Based on this characteristic, the rubber crosslinking accelerator of this application can significantly improve the high temperature resistance and acid and alkali corrosion resistance of rubber compounds, thereby improving the anti-aging properties and service life of rubber compounds, and is suitable for the field of rubber products with high durability requirements.

[0082] The aforementioned sidewall rubber compound is prepared using methods commonly used in the field. For example, the preparation method of the sidewall rubber compound includes: mixing and vulcanizing the base rubber, filler, rubber crosslinking accelerator, vulcanizing agent, and accelerator to obtain the sidewall rubber compound.

[0083] In some specific embodiments, the sidewall compound is obtained according to the following steps:

[0084] Step S1: Using a GE320 internal mixer with a speed of 48 rpm, add the base rubber, carbon black, zinc oxide, lead oxide, stearic acid, protective wax WAX111, antioxidant RD, and antioxidant 4020 to the internal mixer, press the top plug, and mix for 45 seconds; raise the top plug to the correct position, add triethanolamine, press the top plug, adjust the speed to 45 rpm, and mix for 45 seconds; raise the top plug, press the top plug, and mix for 45 seconds; raise the top plug, press the top plug, and mix for 30 seconds; then open the discharge door to discharge the rubber, controlling the discharge temperature at 160-165℃; sheet the rubber from the open mill, cool and collect the rubber to obtain a first-stage masterbatch;

[0085] Step S2: Using a GK255 internal mixer with a speed of 32 rpm, add the first stage of masterbatch, octachlorocyclopentadiene, sulfur, accelerator NS, and anti-scorching agent CTP into the internal mixer, press the top plug, and mix for 45 seconds; raise the top plug, press the top plug, and mix for 40 seconds; raise the top plug, press the top plug, and mix for 40 seconds; open the discharge gate to discharge the rubber, and control the discharge temperature at 100-110℃; sheet the rubber from the open mill, cool and collect the rubber to obtain the rubber compound.

[0086] In the fourth typical embodiment of this application, the application of the rubber crosslinking accelerator provided in the first typical embodiment, the rubber composition provided in the second typical embodiment, or the rubber compound provided in the third typical embodiment is provided in the tire sidewall rubber.

[0087] The rubber crosslinking accelerator, rubber composition, and rubber compound provided in this application, when applied to tire sidewall rubber, enable the matrix rubber to crosslink and generate carbon-carbon single bonds with stronger bond energy and chemical stability, thereby significantly improving high-temperature resistance and acid and alkali corrosion resistance, and broadening the application prospects of tire sidewall rubber.

[0088] The beneficial effects of this application will be further illustrated below with reference to embodiments and comparative examples.

[0089] Example 1

[0090] This embodiment provides a rubber composition comprising, by weight, 100 parts of base rubber (45.0 parts of natural rubber SMR20, 45.0 parts of butadiene rubber BR9000, 10.0 parts of solution-polymerized styrene-butadiene rubber SSBR-HPR850), 47.0 parts of carbon black N347, 2.0 parts of stearic acid, 4.0 parts of indirect zinc oxide, 5.0 parts of rubber crosslinking accelerator (including 2.0 parts of octachlorocyclopentadiene, 1.0 part of triethanolamine, and 2.0 parts of lead oxide), 2.0 parts of antioxidant RD, 2.5 parts of antioxidant 4020, 1.0 part of protective wax WAX111, 0.6 parts of sulfur, 0.5 parts of accelerator NS, and 0.1 parts of scorch inhibitor CTP.

[0091] Example 2

[0092] The difference between this embodiment and Embodiment 1 is that the amount of each component in the rubber crosslinking accelerator has been adjusted. Based on 100 parts by mass of the base rubber, the amount of the rubber crosslinking accelerator is 2.5 parts by mass, of which octachlorocyclopentadiene is 1.0 part by mass, triethanolamine is 0.5 parts by mass, and lead oxide is 1.0 part by mass.

[0093] Example 3

[0094] The difference between this embodiment and Embodiment 1 is that the amount of each component in the rubber crosslinking accelerator has been adjusted. Based on 100 parts by mass of the base rubber, the amount of the rubber crosslinking accelerator is 7.5 parts by mass, of which octachlorocyclopentadiene is 3.0 parts by mass, triethanolamine is 1.5 parts by mass, and lead oxide is 3.0 parts by mass.

[0095] Example 4

[0096] The difference between this embodiment and Embodiment 1 is that the amount of each component in the rubber crosslinking accelerator has been adjusted. Based on 100 parts by mass of the base rubber, the amount of the rubber crosslinking accelerator is 3.7 parts by mass, of which octachlorocyclopentadiene is 1.5 parts by mass, triethanolamine is 0.7 parts by mass, and lead oxide is 1.5 parts by mass.

[0097] Example 5

[0098] The difference between this embodiment and Embodiment 1 is that the amount of each component in the rubber crosslinking accelerator has been adjusted. Based on 100 parts by mass of the base rubber, the amount of the rubber crosslinking accelerator is 6.2 parts by mass, of which 2.5 parts by mass of octachlorocyclopentadiene, 1.2 parts by mass of triethanolamine, and 2.5 parts by mass of lead oxide are used.

[0099] Example 6

[0100] The difference between this embodiment and Embodiment 1 is that the amounts of sulfur and accelerator NS have been adjusted. Based on 100 parts by weight of the base rubber, the amount of sulfur is 0.2 parts by weight and the amount of accelerator NS is 0.1 parts by weight.

[0101] Example 7

[0102] The difference between this embodiment and Embodiment 1 is that the amounts of sulfur and accelerator NS have been adjusted. Based on 100 parts by weight of the base rubber, the amount of sulfur is 1.0 parts by weight and the amount of accelerator NS is 0.8 parts by weight.

[0103] Example 8

[0104] The difference between this embodiment and Embodiment 1 is that the amounts of sulfur and accelerator NS have been adjusted. Based on 100 parts by weight of the base rubber, the amount of sulfur is 1.5 parts by weight and the amount of accelerator NS is 1.0 parts by weight.

[0105] Example 9

[0106] The difference between this embodiment and Embodiment 1 is that the amount of each component in the base rubber has been adjusted. Based on 100 parts by mass of the base rubber, the amount of natural rubber SMR20 is 40.0 parts by mass, the amount of butadiene rubber BR9000 is 40.0 parts by mass, and the amount of solution-polymerized styrene-butadiene rubber SSBR-HPR850 is 20.0 parts by mass.

[0107] Example 10

[0108] The difference between this embodiment and Embodiment 1 is that the amounts of each component in the base rubber have been adjusted. With the base rubber as 100 parts by mass, the amount of natural rubber SMR20 is 50.0 parts by mass, the amount of butadiene rubber BR9000 is 40.0 parts by mass, and the amount of solution-polymerized styrene-butadiene rubber SSBR-HPR850 is 10.0 parts by mass.

[0109] Example 11

[0110] The difference between this embodiment and Embodiment 1 is that the amount of each component in the base rubber has been adjusted. Based on 100 parts by mass of the base rubber, the amount of natural rubber SMR20 is 40.0 parts by mass, the amount of butadiene rubber BR9000 is 55.0 parts by mass, and the amount of solution-polymerized styrene-butadiene rubber SSBR-HPR850 is 5.0 parts by mass.

[0111] Comparative Example 1

[0112] The difference between this comparative example and Example 1 is that the same degree of crosslinking is maintained as in Example 1, but the rubber crosslinking accelerator is removed, and the amount of sulfur is adjusted to 1.5 parts by mass and the amount of accelerator NS is 1.0 parts by mass based on 100 parts by mass of the base rubber.

[0113] Comparative Example 2

[0114] The difference between this comparative example and Example 1 is that the amount of each component in the rubber crosslinking accelerator was adjusted. Based on 100 parts by mass of the base rubber, the amount of the rubber crosslinking accelerator was 1.6 parts by mass, of which 0.8 parts by mass of octachlorocyclopentadiene, 0.3 parts by mass of triethanolamine, and 0.5 parts by mass of lead oxide were used.

[0115] Comparative Example 3

[0116] The difference between this comparative example and Example 1 is that the amount of each component in the rubber crosslinking accelerator was adjusted. Based on 100 parts by weight of the base rubber, the amount of the rubber crosslinking accelerator was 9.0 parts by weight, of which 4.0 parts by weight of octachlorocyclopentadiene, 2.0 parts by weight of triethanolamine, and 3.0 parts by weight of lead oxide were used.

[0117] Comparative Example 4

[0118] The difference between this comparative example and Example 1 is that octachlorocyclopentadiene in the rubber crosslinking accelerator is removed, and the amount of rubber crosslinking accelerator is 3.0 parts by mass based on 100 parts by mass of the base rubber, of which the amount of triethanolamine is 2.0 parts by mass and the amount of lead oxide is 1.0 parts by mass.

[0119] The raw materials and proportions (by mass) of the rubber compositions provided in the embodiments and comparative examples of this application are shown in Table 1:

[0120] Table 1-1

[0121]

[0122] Table 1-2

[0123]

[0124] Test case

[0125] The rubber compositions provided in the above examples and comparative examples were prepared into rubber compound samples. Various performance tests were conducted on the rubber compounds provided in the examples and comparative examples. Specifically, the rubber compound samples were tested for tensile properties and flexural strength before aging, and for tensile properties and tensile volume retention after thermo-oxidative aging, thermal aging, acid solution aging, and alkaline solution aging. The experimental results are shown in Table 2. The rubber compound samples were prepared by vulcanizing the compound produced by an internal mixer using a conventional rubber vulcanization method at a temperature of 150°C for 30 minutes.

[0126] (1) Tensile property test method: The tensile properties of vulcanized rubber were tested according to GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The higher the tensile strength and elongation at break, the higher the tensile properties and the better the performance.

[0127] (2) Flexural rating test method: The rubber sample was subjected to 3 million flexural cycles and the flexural rating was determined according to GB / T 13934-2006 "Determination of Flexural Cracking and Crack Growth of Vulcanized Rubber or Thermoplastic Rubber (Demercia Type)". The lower the flexural rating, the better the flexural performance.

[0128] (3) Tensile volume retention rate: (tensile strength × elongation at break) after aging / (tensile strength × elongation at break) before aging × 100%. The higher the tensile volume retention rate, the higher the heat and oxygen aging resistance.

[0129] (4) Thermo-oxidative aging method: The rubber samples provided in the examples and comparative examples were placed in an electric heating drying oven. The temperature of the electric heating drying oven was 100°C and the heating time was 48 hours.

[0130] (5) Thermal aging (high temperature aging) method: The rubber samples provided in the examples and comparative examples are placed in an electric heating drying oven. Nitrogen gas is introduced into the electric heating drying oven. Under the protection of nitrogen gas, an airless aging test is carried out. The temperature of the heating oven is 100°C and the heating time is 48 hours.

[0131] (6) Acid solution corrosion aging method: First, prepare the rubber samples provided in the examples and comparative examples into type I dumbbell test pieces, and then soak the type I dumbbell test pieces in 0.01 mol / L hydrochloric acid solution for 48 hours.

[0132] (7) Alkaline solution corrosion aging method: First, prepare the rubber samples provided in the examples and comparative examples into type I dumbbell test pieces, and then soak the type I dumbbell test pieces in 0.01 mol / L NaOH solution for 48 h.

[0133] Table 2-1

[0134]

[0135]

[0136] Table 2-2

[0137]

[0138]

[0139] As can be seen from the comparison between Examples 1-11 and Comparative Examples 1-4, the rubber composition provided in this application, by using specific amounts of matrix rubber, rubber crosslinking accelerator, accelerator and vulcanizing agent in synergy, and by using rubber crosslinking accelerator to replace part of the traditional vulcanizing agent and accelerator, the overall performance of the prepared rubber compound is greatly improved.

[0140] A comparison of Examples 1-7, Examples 9-11 and Example 8 shows that when the amount of vulcanizing agent and accelerator is too high, although the mechanical properties of the rubber compound are excellent, its flexural properties are reduced due to the excessive crosslinking density.

[0141] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0142] Applying the technical solution of this application, the rubber crosslinking accelerator provided includes octachlorocyclopentadiene, triethanolamine, and lead oxide. Octachlorocyclopentadiene can act as a crosslinking agent for diene rubbers, lead oxide acts as a chlorine acceptor, and triethanolamine acts as a chlorine activator. These three components work synergistically in a specific ratio, capable of replacing some traditional vulcanizing agents and accelerators. Unlike traditional sulfur and sulfenamide accelerator systems, the rubber crosslinking accelerator provided in this application generates carbon-carbon single bonds during the crosslinking process of the rubber matrix, rather than sulfur-containing bonds (such as monosulfide, disulfide, or polysulfide bonds) in traditional systems. The bond energy of carbon-carbon single bonds is significantly higher than that of sulfur-containing bonds, resulting in stronger chemical stability. Therefore, vulcanized rubber with carbon-carbon single bonds has significant advantages in high-temperature resistance and acid and alkali corrosion resistance. In contrast, traditional sulfur-containing bonds are easily broken under high-temperature or acid / alkali environments, leading to a decline in the performance of the vulcanized rubber. Based on this characteristic, the rubber crosslinking accelerator provided in this application can significantly improve the high temperature resistance and acid and alkali corrosion resistance of vulcanizates, thereby improving the anti-aging properties and service life of vulcanizates, and is suitable for the field of rubber products with high durability requirements.

[0143] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A rubber crosslinking accelerator, characterized in that, The rubber crosslinking accelerator includes octachlorocyclopentadiene, triethanolamine and lead oxide, and the mass ratio of the three is (1.0-3.0):(0.5-1.5):(1.0-3.0).

2. A tire sidewall rubber composition, characterized in that, The rubber composition comprises, by weight parts: 100 parts of base rubber, 2.5 to 7.5 parts of the rubber crosslinking accelerator as described in claim 1, 0.1 to 0.8 parts of accelerator, and 0.2 to 1.0 parts of vulcanizing agent.

3. The sidewall rubber composition according to claim 2, characterized in that, Based on 100 parts by weight of the base rubber, the amount of octachlorocyclopentadiene is 1.0 to 3.0 parts by weight, the amount of triethanolamine is 0.5 to 1.5 parts by weight, and the amount of lead oxide is 1.0 to 3.0 parts by weight.

4. The sidewall rubber composition according to claim 2, characterized in that, The base rubber includes natural rubber, butadiene rubber, and styrene-butadiene rubber. Based on 100 parts by weight of the base rubber, the amount of natural rubber is 40.0 to 50.0 parts by weight, the amount of butadiene rubber is 40.0 to 55.0 parts by weight, and the amount of styrene-butadiene rubber is 5.0 to 20.0 parts by weight. And / or, the accelerator is accelerator NS; And / or, the vulcanizing agent is sulfur.

5. The sidewall rubber composition according to claim 2, characterized in that, The rubber composition further includes at least one of fillers and additives; Preferably, based on 100 parts by weight of the base rubber, the amount of filler is 40.0 to 55.0 parts by weight; Preferably, the additives include at least one of antioxidants, activators, and anti-scorching agents; Preferably, based on 100 parts by weight of the base rubber, the additives include 2.8 to 7.5 parts by weight of the antioxidant, 3.5 to 9.0 parts by weight of the activator, and 0.1 to 0.3 parts by weight of the scorch inhibitor.

6. The sidewall rubber composition according to claim 5, characterized in that, The filler is carbon black, which includes at least one of carbon black N330, carbon black N347, carbon black N375, carbon black N326, and carbon black N351. Preferably, the antioxidant includes at least one of wax-based antioxidants, quinoline-based antioxidants, and p-phenylenediamine-based antioxidants; Preferably, based on 100 parts by weight of the base rubber, the rubber composition comprises 0.8-2.0 parts by weight of a wax-based antioxidant, 1.0-2.5 parts by weight of a quinoline-based antioxidant, and 1.0-3.0 parts by weight of a p-phenylenediamine-based antioxidant; Preferably, the wax-based anti-aging agent includes at least one of protective wax WAX111 and protective wax HG72; Preferably, the quinoline antioxidant includes antioxidant RD; Preferably, the p-phenylenediamine antioxidant includes antioxidant 4020.

7. The sidewall rubber composition according to claim 5, characterized in that, The anti-scorching agent is CTP; And / or, the activator includes zinc oxide and stearic acid; Preferably, based on 100 parts by weight of the base rubber, the rubber composition comprises 2.5 to 6.0 parts by weight of zinc oxide and 1.0 to 3.0 parts by weight of stearic acid.

8. A tire sidewall rubber compound, characterized in that, The raw material for the sidewall rubber compound is the rubber composition according to any one of claims 2 to 7.

9. A method for preparing the sidewall rubber compound according to claim 8, characterized in that, Includes the following steps: The base rubber, filler, rubber crosslinking accelerator, vulcanizing agent, and accelerator are mixed and vulcanized to obtain the sidewall rubber compound.

10. The use of a rubber crosslinking accelerator according to claim 1, a sidewall rubber composition according to any one of claims 2 to 7, or a sidewall compound according to claim 8 in a tire.

Images